Pump



P. J. ZANONI A ril 18, 1967 PUMP Filed Sept. 4, 1964 FIG.

FIG. 2

INVENTOR. PAUL .I'ZA/VON/ ATTORNEY United States Patent G Filed Sept. 4, 1964, Ser. No. 394,439 8 Claims. (CI. 60-67) This invention relates to pumps and, more particularly, to such which may be arranged in a series, or staged so that the pressure increase produced in each stage is additive to that produced in a successive stage or in successive stages. a

An object of my invention is to provide a pump operable without solid moving parts and powered by low pressure steam extracted at one or more places from a device or devices using such steam, and replacing the normal feed water heaters and injectors or pumps currently used for feeding water to a boiler.

Another object of my invention is to provide a steam pump for feeding water to a boiler, in which energy is imparted to the pump stream by placing a liquid jet ahead of a steam jet, that is, adding the steam between a liquid jet and a diffusor, thereby avoiding impact losses.

A further object of my invention is to provide a steam pump for feeding boilers which uses low pressure or exhaust steam which enters the device without the aid of a live steam jet.

. A still further object of my invention is to provide a steam pump for boiler feed water which uses steam at several pressures intermediate those at the boiler end condenser.

These and other objects and advantages will become apparent from the following detailed description when taken with the accompanying drawings. It will be understood that the drawings are for the purposes of illustration and do not define the scope or limits of the invention, reference being bad for the latter purpose to the appended claims.

In the drawings, wherein like reference characters denote like parts in the several views:

FIGURE 1 is a longitudinal sectional diagrammatic view of a steam pump embodying my invention.

FIGURE 2 is an assembly view diagrammatically showing how such a pump may be used in combination with a boiler, a device using steam such as a turbine, and a condenser.

It has long been recognized that a steam injector may be used to supply preheated water, either by itself or in series with a feed water heater receiving exhaust or partially expanded steam. Also a boiler feed pump may be used for driving feed water from the condenser through such heaters to the boiler. It has been assumed that in connection with a single stage injector, there was a maximum temperature at which the feed water could be supplied to the injector and also that there was a maximum temperature, below 212 F., at which the commingled stream of feed water and condensed injector steam could be delivered to a boiler.

As is generally known, the total intrinsic energy of a stream of steam entering an injector is used in part to raise the kinetic energy of the combined feed water and condensed injector steam and in part to raise the temperature of this combined stream. This kinetic energy is subsequently transformed into pressure energy in a diffusor or tapered delivery pipe of the injector in order to force the feed water into the boiler against the working pressure of the fluid therein.

I have found that by using a pump in which a stream of recirculating water is fed, into the main stream from the condenser, ahead of the steam jet, thereafter, diffused in an expanding conduit, and wherein such a device may be 3,314,236 Patented Apr. 18,1967

ICE

used by itself or in series with one or more similar devices for increasing the boiler feed injection pressure, the top limit of feed temperature as hitherto understood can be considerably exceeded. I may, thereby, recover more heat energy of the working fluid that is part of the intrinsic energy of the steam employed, which appears in the commingled stream as increase of temperature in the water delivered.

When applied to a steam power plant, the invention offers advantages additional to those associated immediately with the compounding or staging of pumps. As is well known, auxiliaries such, for example as feed pumps, air pumps, and lighting power plants in locomotives or other power units, do not use the steam expansively, or do so only to a small degree. There is thus provided a plurality of ready sources of supply of steam at different pressures. It is not, therefore, necessary to use the highest-pressure steam in any stage of the pump. The first stage may use steam at the lowest suitable pressure, and each successive stage may be supplied with steam at successively higher pressures.

In this way, each pump stage does not function merely as a stage in the upgrading of the temperature and pressure of feed water, but also as a second expansion stage of the incompletely expanded steam from the auxiliaries or main steam unit. It will also 'be understood that the same principle applies to using the steam from a turbine which may be tapped at different pressures or degrees of expansion for use in the various stages of my pump.

Referring to the drawings in detail, and first considering the diagrammatic showing of my pump it in FIG- URE 1, water flows from the suiable supply, which may be a condenser such as that designated 11 in FIGURE 2, into a conduit 12 forming a part of my pump, said water flowing at a relatively low velocity and under a pressure designated P The main stream is then accelerated, as by restriction of the conduit across section in a region therebeyond to produce a water jet at 13. Such acceleration reduces the pressure of the water to that designated P The water in the jet at 13, being supplied from a higher pressure region of the device, will issue at a velocity higher than that of the main stream before restriction, and also higher than that at the restricted portion.

At this point, steam is introduced through a pipe 14 as a jet directly'into and expands beyond the water jet. The mixture then passes on to a mixing portion between said steam jet and the section 15, where further expansion and acceleration takes place. The function of the steam jet is to add useful energy to the stream and get momentum as in the conventional steam jet injector. Therefore, the steam velocity should exceed the water velocity by an amount only necessary to achieve control of the steam flow, by having it higher than that of the water. It should enter the stream as smoothly as possible in order to avoid excessive turbulence and other irreversibilities.

The so produced fluid mixture is then decelerated in a difiusor section 15, by the combined action of an increase in cross-sectional area and condensation of the steam. Such deceleration increases the pressure of the stream and, therefore, the saturation temperature of the mixture as flow proceeds along the diifusor. At the same time, condensation of the steam increases the water temperature. At the end of the difiusor, the steam has all condensed and, because of the aforementioned action therein, the pressure has risen to P which is greater than P A portion of water in the stream is then separated and recirculated as through conduit 16, in order to supply extra water at the water jet 13. The recirculated water mixes with the water jet, forming a main stream. In accordance with the law of conservation of momentum, the entire flow assumes some velocity between that of the water jet and the recirculated flow before mixing. It is important that the actual water temperature is exceeded by the saturated steam temperature at all times, in order to insure continuous condensation of the steam. Thus, under certain conditions it may be necessary to cool the recirculation water which flows to the water jet to insure such condensation.

The discussion following will show some of the advantages of recirculating some of the water, as distinguished from using only steam ahead of the jet 13.

(1) The mixing of two streams is known to be governed by a conservation of momentum, i.e., the total momentum entering is equal to the momentum leaving.

(2) The (reversible) energy entering the device is its kinetic energy if the temperatures of the two streams are equal.

As an example, we can calculate the amount of water in the motive stream (recirculation) necessary to accelerate 1 lb. of water in the main stream from 10 ft./sec. to 30 ft./sec, Assume the motive stream entering the mixing portion is moving with a velocity of 100 ft./sec.

Momentum is defined as M :m-v, where M=rnomenturn, m=mass, and v=velocity. Entering momentum is equal to leaving momentum.

1 (1b.) X l+m l0O=(l l-m -30 where m =mass of driving stream (water).

In =.28 lb.

KB main stream: =50/g. ft. lbs.

where g=acceleration due to gravity in ft. per sec. per sec.

Total entering=1450/g. ft. lbs.

KE' motive stream =1400/g. ft. lbs.

Leaving:

Total loss of reversible energy=874/ g. ft. lbs.

KE =576/g. ft. lbs.

In a conventional injector, the motive stream is steam which is expanded to high velocity in a nozzle. Assuming that the steam enters the mixing chamber at 2000 ft./sec., and equating the entering and leaving momenta as before:

10(lbs.)+2000m,=(1+m where m =mass of driving stream (steam).

Note that considerably less steam is required in this instance than water in the preceding instance.

As to the kinetic energy here involved, we have entering:

KE main stream=/ g. ft. lbs.

Total entering=20450/g. ft. lbs.

Leaving:

KE motive stream =20400/g. ft. lbs.

=455/g. ft. lbs.

Total loss of KE=l9995/g. ft. lbs.

This loss of kinetic energy is known as the impingement loss and referred to in many patents. Using a larger quantity of low velocity motive fluid, in accordance with my invention, avoids a considerable portion of this loss.

The remainder of the water, after drawing olI that for recirculation, is the useful output that proceeds either to the next stage of the pump, such as that designated 10 in FIGURE 2, which may be identical in principle with the one described, or to the end use such as the boiler, designated 17 in FIGURE 2.

A specific application of this device is shown as a mere example, where my pump or pumps replace the conventional boiler feed pump or injector for feed water heaters in a conventional regenerative steam power plant. Such an application is illustrated specifically in FIGURE 2, as there is shown a steam generating boiler 17, steam from which passes through live steam pipe 18 to, in this instance, a steam turbine 19, as representative of a device using such live steam. The remainder of the steam not used in the steam pumps 10 and 10, which embody my invention, passes to the condenser 11 through exhaust steam pipe 21.

The pump 10 is constructed as illustrated in FIGURE 1, the conduit from the condenser being that designated 12 in said figure, and the portion of the pump conduit beyond the recirculating water conduit 16 feeding to the conduit 12' of the second stage pump 10, which is constructed similarly to the first stage pump 10 and has a recirculating water conduit 16'.

The only difierence in operation between the pumps 10 and 10 is that the pump 10 receives relatively low pressure steam through pipe 22 from the turbine 19, whereas the pump 10' receives steam at a higher pressure, or that not expanded to the same extent as the steam fed through the pipe 22, said higher pressure steam passing to the pump 10 through the pipe 23. In both instances, the steam fed through the pipes 22 and 23 produce steam jets in the pumps corresponding with that produced by the steam fed through the pipe 14 in FIGURE 1, representing an internal continuation of the pipe 22.

In this instance I have shown steam pumps used with a steam turbine. However, it will be understood that it may similarly be used with a reciprocating steam engine, or other device using steam, just so steam may be tapped therefrom at one or more pressures above atmospheric. It will also be understood that, in addition to the partially exhausted steam fed through the pipes 22 and 23, I may also use steam from auxiliaries not here shown.

Although the invention has been described with reference to water and steam, it is adaptable for use with other liquid or liquifiable materials and their vapors, or gases, such as vaporizable metals or salts. It will also be understood that I may employ as the driving force the vapor of material other than that of the liquid stream, the con densed liquids to be later separated.

Having now described my invention in detail in accordance with the requirements of the patent statutes, those skilled in this art will have no difiiculty in making changes or modifications in the individual parts or their relative assembly in order to meet specific requirements or conditions. Such changes and modifications may be made without departing from the scope and spirit of the invention, as set forth in the following claims.

I claim:

1. A pump for delivering preheated feedliquid to a boiler comprising a conduit providing for the flow of a main stream of liquid at a relatively low velocity, a restriction in said conduit through which said main stream flows to effect acceleration, and reduction in pressure, of said stream, providing a liquid jet, a nozzle through which a vapor issues and expands beyond the jet, a mixing chamber where further expansion and acceleration takes place, an expanding difiusor portion of said conduit, through which said stream flows after condensing the vapor directed thereto, thereby effecting an increase in stream pressure, a by-pass conduit at the end of said diffusor portion, through which a portion of said stream flows back to form means recirculating a portion of said liquid to mix with said liquid jet before the vapor engages said stream, and means conveying the remainder of said stream of liquid toward said boiler.

2. In combination with a pump as recited in claim 1, a device using such vapor, a condenser, means directing exhaust vapor from said device to said condenser, means conducting the output of said condenser to said conduit providing for the flow of a main stream of liquid, and means connecting said nozzle to receive only partially expanded vapor from said vapor-using device.

3. In combination with a pump as recited in claim 1, wherein the expanding diffusor portion of said conduit is connected in series with a conduit providing for the flow of a main stream of liquid to a similar pump, from the diifusor portion of which the remainder of the stream of liquid is conveyed toward said boiler.

4. In combination with a pump as recited in claim 2, wherein, when the expanding diifusor portion of said conduit is connected in series with a conduit providing for the flow of a main stream of liquid to a similar pump, from the ditfusor portion of which the remainder of the stream of liquid is conveyed toward said boiler.

5. A pump for delivering preheated feedwater to a boiler comprising a conduit providing for the flow of a main stream of water at a relatively low velocity, a restriction in said conduit through which said main stream flows to effect acceleration, and reduction in pressure, of said stream, providing a water jet, a nozzle through which steam issues and expands beyond the jet, a mixing chamber where further expansion and acceleration takes place, an expanding difiusor portion of said conduit, through which said stream flows after condensing the steam directed thereto, thereby effecting an increase in stream pressure, a by-pass conduit at the end of said diffusor portion, through which a portion of said stream flows back to form means recirculating a portion of said water to mix with said water jet, before the steam engages said stream, and means conveying the remainder of said stream of water toward said boiler.

6. A pump for delivering preheated feedwater to a boiler comprising a conduit providing for the flow of a main stream of water at a relatively low velocity, a restriction in said conduit through which said main stream then flows to effect acceleration, and reduction in pressure, of said stream, providing a water jet, means recirculating a portion of the water used and directing it to mix with said jet, a nozzle through which steam issues and expands beyond the zone of mixing of the jet and recirculated waters, a mixing chamber where further expansion and acceleration takes place, an expanding difiusor portion of said conduit, through which said stream flows after condensing the steam directed thereto, thereby effecting an increase in stream pressure, and a -by-pass conduit at the end of said diffusor portion, through which a portion of said stream flows back to produce the means recirculating a portion of said water to mix with said jet, and means conveying the remainder of said stream of water toward said boiler.

7. The method of delivering preheated feedliquid to a boiler comprising conveying a main stream of said liquid at a relatively low velocity through a conduit, accelerating said stream while reducing its pressure, thereby providing a liquid jet, directing a jet of a vapor into the liquid issuing as said liquid jet, conducting the commingled liquid and vapor while allowing first expansion, reduction of pressure and acceleration, followed by diffusion and reduction in the velocity with condensation of the vapor and increasing pressure, directing a portion of the stream back to mix with said liquid jet before the vapor engages it, and conveying the remainder of said stream of liquid toward its ultimate use.

8. The method of delivering preheated feedwater to a boiler comprising conveying a main stream of water at a relatively low velocity through a conduit, accelerating said stream while reducing its pressure, thereby providing a water jet, directing a jet of steam into the water issuing as said water jet, conducting the commingled water and steam while allowing first expansion, reduction of pressure and acceleration, followed by diffusion and reduction in velocity with condensation of the steam and increasing pressure, directing a portion of the stream back to mix with said water jet before the steam engages it, and conveying the remainder of said stream of water toward its ultimate use.

References Cited by the Examiner UNITED STATES PATENTS 1,504,723 8/1924 Schmidt 103267 X 2,270,911 1/ 1942 Tinker 1035 2,670,597 3/ 1954 Villemejane 39.52 X

FOREIGN PATENTS 592,994 2/ 1934 Germany.

MARTIN P. SCHWADRON, Primary Examiner.

ROBERT R. BUNEVICH, SAMUEL LEVINE,

Examiners. 

1. A PUMP FOR DELIVERING PREHEATED FEEDLIQUID TO A BOILER COMPRISING A CONDUIT PROVIDING FOR THE FLOW OF A MAIN STREAM OF LIQUID AT A RELATIVELY LOW VELOCITY, A RESTRICTION IN SAID CONDUIT THROUGH WHICH SAID MAIN STREAM FLOWS TO EFFECT ACCELERTION, AND REDUCTION IN PRESSURE, OF SAID STREAM, PROVIDING A LIQUID JET, A NOZZLE THROUGH WHICH A VAPOR ISSUES AND EXPANDS BEYOND THE JET, A MIXING CHAMBER WHERE FURTHER EXPANSION AND ACCELERATION TAKES PLACE, AN EXPANDING DIFFUSOR PORTION OF SAID CONDUIT, THROUGH WHICH SAID STREAM FLOWS AFTER CONDENSING THE VAPOR DIRECTED THERETO, THEREBY EFFECTING AN INCREASE IN STREAM PRESSURE, A BY-PASS CONDUIT AT THE END OF SAID DIFFUSOR PORTION, THROUGH WHICH A PORTION OF SAID STREAM FLOWS BACK TO FORM MEANS RECIRCULATING A PORTION OF SAID LIQUID TO MIX WITH SAID LIQUID JET BEFORE THE VAPOR ENGAGES SAID STREAM, AND MEANS CONVEYING THE REMAINDER OF SAID STREAM OF LIQUID TOWARD SAID BOILER. 